package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import io.lettuce.core.RedisCommandExecutionException;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.RedisSystemException;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private IVoucherOrderService proxy;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    // 队列和线程池
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    // 初始化线程
    @PostConstruct
    private void init() {
        //在初始化时添加消费者的逻辑（如果没有的话）
        SummerStart();
        // 启动线程监听
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private void SummerStart() {
        try {
            stringRedisTemplate.opsForStream().createGroup("stream.orders", ReadOffset.latest(), "g1");
        } catch (RedisSystemException e) {
            //用于判断redis消费者组是否已经存在
            if (e.getCause() instanceof RedisCommandExecutionException
                    && e.getCause().getMessage().contains("BUSYGROUP")) {
                //如果已经存在会抛出错误
                log.warn("消费者组已存在，无需重复创建");
            } else {
                throw e;
            }
        }
    }

    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    //处理异常消息
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有异常消息，结束循环
                        break;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pendding订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (Exception e1) {
                        e1.printStackTrace();
                    }
                }
            }
        }
    }

    @Override
    @Transactional
    public void createVoucherOrder(VoucherOrder order) {
        Long userId = order.getUserId();
        int count = query()
                .eq("user_id", userId)
                .eq("voucher_id", order.getVoucherId())
                .count();
        if (count > 0) {
            log.error("用户 {} 已下单过", userId);
            return;
        }

        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", order.getVoucherId())
                .gt("stock", 0)
                .update();

        if (!success) {
            log.error("库存不足，扣减失败");
            return;
        }

        save(order);
    }
    // 异步下单线程类
/*    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    VoucherOrder order = orderTasks.take();
                    handleVoucherOrder(order);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }*/

    private void handleVoucherOrder(VoucherOrder order) {
        Long userId = order.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = false;
        try {
            isLock = lock.tryLock();
            if (!isLock) {
                log.error("用户重复下单: {}", userId);
                return;
            }
            proxy.createVoucherOrder(order);
        } catch (Exception e) {
            log.error("订单处理失败", e);
        } finally {
            if (isLock) {
                lock.unlock();
            }
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");

        // 调用 Lua 脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );

        int r = result != null ? result.intValue() : -1;
        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        // 获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }

  /*  @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");

        // 调用 Lua 脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );

        int r = result != null ? result.intValue() : -1;
        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        // 放入阻塞队列
        VoucherOrder order = new VoucherOrder();
        order.setId(orderId);
        order.setUserId(userId);
        order.setVoucherId(voucherId);
        orderTasks.add(order);

        // 获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }*/


}
